M16A4

It behaves almost identically to Call of Duty: Modern Warfare with some small differences. It is now unlocked at level 40 in multiplayer. Its reload animation is now identical to that of the M4A1 Carbine. To make it look more modernized, a Picatinny Rail has been placed on the carrying handle, and has a synthetic handguard with RIS Rails at the end. The rear sight aperture has been made thinner than the Call of Duty 4: Modern Warfare version, making using the iron sights much easier.

The M16A4 has barely been changed from Call of Duty 4. The only known difference is that the time between bursts has been increased from 0.2 seconds to 0.28 seconds, and the only other possible differences would be in recoil and rate of fire per burst. The FAMAS is essentially identical to the M16A4 except that it fires faster per burst but has an increased delay of 0.32 seconds between bursts. It is recommended to have FMJ as the gun has a high penetration rate and the red dot sight. In comparison to its Call of Duty 4 counterpart, it takes a noticeably longer period of time to aim down the sight with the Modern Warfare 2 version of the M16A4.

While holding the gun at the hip, the Heartbeat Sensor appears just slightly to the left and below the center of the screen which makes it very easy to see. Unfortunately, while reloading grenades into the Grenade Launcher, the Heartbeat Sensor covers the entire middle of the screen.

In single player, the M16A4 is seen in both American and Task Force 141 missions, although the FAMAS is much more predominant. It fires in bursts in both singleplayer and multiplayer, unlike its Call of Duty 4 counterpart